| Magnetron sputtering deposition coating is an important one of the current coating methods.Compared with other coating methods,magnetron sputtering coating can obtain films with good density,adhesion and other properties.It is also often used for the coating of particle surface.Magnetron sputtering particle surface coating is less research on the equipment at present,the internal particle accumulation problem has not been studied in depth,the coating process is consistent with the traditional material coating process,no effective measures to prevent the particles themselves from the situation of accumulation,resulting in low particle surface coating coverage,coating uniformity is poor and other problems.Combined with the law of particle movement,the particle movement and magnetic field distribution inside the magnetron sputtering equipment were designed,and the internal equipment was analyzed and studied.According to the characteristics of easy accumulation in the process of particle coating and the characteristics of uneven distribution of sputtering ions,the particle coating uniformity was analyzed:(1)Based on the coating characteristics of magnetron sputtering,target atoms of target materials sputtered are the source of particle films.In order to expand the coating range of particle magnetron sputtering and improve the uniformity of particle coating,the magnetic field and electron cloud distribution of the target are studied.Simulation software was used to simulate the magnetron sputtering vacuum chamber.With reference to laboratory equipment parameters,the coercive magnetic strength of internal and external magnets was set as 400kA/m,and the magnetic target spacing was set as 15mm(distance between external magnets and target).Through simulation,the distribution area of electron clouds gathered on the surface of target in the shape of rings during sputtering.The highest point of the electron cloud on the surface of the target material is 18.1mm from its center,and the magnetic field intensity at this point is also the maximum.The highest intensity is 42mT,which is the same as the electron cloud distribution.Then through the study of the experimental target of magnetron sputtering,the average size of the inner ring and the outer ring of the etched orbit on the surface of the target is 31.5mm and 46.4mm respectively,and the corresponding relationship among the horizontal field intensity of the magnetic field of the target,the dense distribution area of the electron cloud and the sputtering area of the target atoms is determined.(2)Based on the relationship between the magnetic field and the electron cloud of the target material,the electron cloud distribution is changed by changing the magnetic field.According to the change of the magnetic field of the target in five different ways,the distance between the outer magnetic ring and the target is 6～14mm,and the magnetic field intensity near the target is maintained between 46.2～54.6mT,while the magnetic field intensity required by magnetron sputtering is 25mT～60mT,and the magnetic field intensity is in line with this range.The distribution of electron cloud on the surface of the target material in the variation range of Δ24mm the variation range is large enough,the electron density is also in line with the required value of magnetron sputtering,so the best effect is determined by changing the position of the external magnet.After the design of lifting mechanism to complete the magnet position change,lifting mechanism can complete the magnet in the 6～14mm range of constant change,so that the sputtering source is a ring scale,below the particle sputtering area also changes,thus increasing the probability of particles being plated,promote the particle surface coating uniformity.(3)Because the uniformity of particle coating also depends on the movement characteristics of particles,controlling the movement process of particles is also an important guarantee of uniformity.By applying motion to the particles directly,the internal particles can maintain better dispersion and fluidity during sputtering coating,so as to avoid the uneven coating caused by particle accumulation.This time,the discrete element simulation software is used for particle simulation,to apply rotation and vibration to the particle container,analyze the motion speed and trajectory of the internal particles,and then constantly change the vibration frequency and speed of the container,analyze the impact on the particles,and finally determine the vibration frequency of 15Hz,the speed of 3rad/s,The motion effect of the internal particles reaches the best state,and the particles maintain a certain regular running track inside the container.The particles with different qualities and shapes turn up and down at this vibration frequency and speed,without stacking,so as to ensure the uniformity of the internal particle coating process.(4)A corresponding vessel vibration mechanism was designed based on vibration frequency and speed,and three-dimensional modeling was carried out on the mechanism through Creo.Finite element stress analysis was carried out on the rotating shaft.Finite element analysis by workbench showed that the maximum stress point of the rotating shaft was 63.9Mpa,and the rotating shaft met the strength requirements.At the same time,the modal analysis and harmonious response analysis of the rotating shaft and rotating support are also carried out.Their natural frequency is above 500Hz,smaller than the working frequency of the vibration mechanism,which can avoid the damage caused by resonance.(5)According to the above requirements of target magnetic field lifting mechanism and vibration mechanism,some key components of magnetron sputtering equipment are designed.The height of the vacuum chamber is determined to be 490mm according to the lifting target magnetic field and the height of the vibration mechanism,which is higher than that of the general equipment coated with common materials.Its diameter is set to 350mm,which is the same as that of the general equipment.The vacuum chamber adopts the double-layer water cooling method,and the wall thickness calculated by the design of austenitic stainless steel is 3mm and the middle cooling layer is 4mm.The magnetic field lifting mechanism and particle vibration mechanism are rationally arranged.In the design process,a vacuum partition is added on the premise that the vacuum premise wall thickness is determined.The external magnet lifting mechanism also adds a vacuum partition to ensure that the internal reworking process is always in a vacuum state.The last part of the design is the selection and calculation of the vacuum pump,as well as the selection of the vacuum detection ionization gauge.The 3D models of the above parts inside the cavity are modeled and assembled by Creo.The overall mechanism around the particle coating uniformity research,through the particle container movement mechanism to disperse the internal particles and the magnetic field lifting mechanism to make the target sputtering source constantly change,the two work together,so as to meet the requirements in the process of magnetron sputtering particle coating,keep the particle surface coating uniformity in the container. |
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